This invention relates to ultrasonic proximity sensors and, more particularly, to an improved ultrasonic proximity sensor utilizing polymer piezoelectric film in the transducer assembly.
Proximity sensors have many applications. For example, a proximity sensor mounted to a vehicle can provide a warning to the vehicle operator of the presence of an obstruction in the path of the vehicle. Thus, a proximity sensor mounted to the rear of a truck which is backing toward a loading dock can be utilized to alert the truck driver of the remaining distance to the loading dock. It is therefore an object of the present invention to provide a proximity sensor which may be utilized for such an application.
A proximity sensor utilizing radiated and reflected ultrasonic acoustic waves is a desirable form for use in such an application. The desired beam pattern for obstruction detection applications is a straight, wide and thin beam. It is therefore another object of the present invention to provide a transducer assembly for generating an ultrasonic acoustic wave having such desired beam pattern.